Electron tube socket



Aug. 25, 1959 NQBLE ETAL 2,901,678

ELECTRON TUBE SOCKET Filed Oct. 5; 1956 2 Sheets-Sheet' 2 26 II EA- LOWELL 4/1 0545 ATTORNEY United States Patent ""ce ELECTRON TUBE SOCKET Lowell A. Noble and Richard H. Chamberlin, San Bruno, Calih, assignors to Eitel-McCullough, Inc., San Bruno, Calif., a corporation of California Application October 5, 1956, Serial No. 614,236

9 Claims. (Cl. 317-257) This invention relates generally to an electron tube socket, and more particularly to an electron tube socket for use with tubes which deliver relatively large amounts of power in the higher frequency ranges.

Generally, when operating at relatively high powers, air must be circulated past the tube to maintain the same at safe operating temperatures. It is desirable to circulate the air axially along the tube for the most efficient cooling and economic blower requirements.

When operating tubes in the higher frequency ranges the socket forms part of the high frequency circuit. Consequently it is important to have a socket which has suitable high frequency characteristics.

It is a general object of the present invention to provide an improved electron tube socket.

It is another object of the present invention to provide an electron tube socket in which the body portion is in the form of a ring through which air may be easily circulated.

It is still another object of the present invention to provide an electron tube socket which is suitable for use in the higher frequency ranges.

It is a further object of the present invention to provide an electron tube socket which includes a screen bypass capacitor.

It is another object of the invention to provide an electron tube socket having an improved contact arrangement for engaging a ring-type terminal on an associated electron tube.

It is a further object of the invention to provide an electron tube socket which includes an encapsulated capacitor.

It is another object of the invention to provide an electron tube socket having a capacitor structure so arranged as to facilitate encapsulation by waterproofing dielectric material.

It is still a further object of the present invention to provide an electron tube socket which is suitable for use with tubes of the type described in Patent No. 2,472,942, which tube operates in the higher frequency ranges and which requires eflicient cooling of the anode structure.

The invention possesses other objects and features of advantage, some of which, with the foregoing, will be set forth in the following description of the invention. It is to be understood, of course, that the invention is not to be limited to the particular disclosure of species of the invention, as other variant embodiments may be adopted within the scope of the appended claims.

Referring to the drawing:

Figure 1 is an elevational view showing the lower portion of an electron tube and the socket in section;

Figure 2 is an enlarged sectional view of a portion of the socket;

Figure 3 is a perspective view showing an electron tube mounted in a socket constructed in accordance with the invention.

Figure 4 is a sectional view taken along the line 44 of Figure 1; and

\ 2,901,678 Patented Aug. 25, 1959 Figure 5 is a bottom view of the electron tube socket.

The electron tube illustrated comprises an anode portion 11 which is supported by a vitreous wall 12 and which includes a base portion 13. The anode includes a fin structure 14 to efliciently cool the anode. The internal electrodes of thetube may comprise a cathode, control grid, and screen grid. Generally, the screen grid is con nected to the ring 16 of the bottom portion of the electron tube. The control grid is connected to the central prong 17 which is provided with a guide key 18 for indexing the tube in the socket. The cathode is connected to a plurality of the prongs 19 which are disposed annularly about the central prong 17. By employing a plurality of the prongs, the cathode is more rigidly supported. Higher cathode currents may be applied through the prongs. It is, of course, to be understood that more or less grids may be included and that the grids could each be suitably connected to one or more of the annular prongs 19.

The socket designated generally by the reference numeral 21 comprises a ring-like body 22 made of suitable dielectric material, having a plurality of segments 23 which extend radially inward. A web-like portion 24 extends downwardly and serves to support the guide keyway and contacts for the central prong 17, as will be presently described.

Contact receiving recesses 26 (Figure 4) are formed on the upper side of the body. The recesses extend from the ring portion of the body radially inward into each of the segments. The recesses are generally triangular in shape with a radially extending slot 27. Axial slots 28 are formed in the body adjacent the outer edge of the recesses 26. The slots 28 serve to receive the lead portion of the contact elements 29.

The contact elements are formed from resilient strip material and have a generally triangular portion 31 which is received by the associated recess. The free ends 32 of the strip extend parallel to one another and are accommodated in the radial slot 27. The finger-like ends are shaped to form prong-receiving apertures 33 which resiliently and removably receive the prongs. The finger-like ends which form the prong receiving aperture 33 are inclined outward from one another near the upper surface thereof to form a camming surface which serves to guide the prongs as they are engaged by the same. Each contact element includes a portion 34 which is at right angles to the triangular portion 31 which is adapted to extend downwardly through the axial slots 28. The portions 34 provide means which are readily adapted for connection to appropriate lead wires.

A contact retainer 35 is placed over the body after the contacts are seated in the recesses and is suitably attached thereto. For example, the contact retainer 35 may be secured to the body 22 by means of the tubing 36 which has its ends flared over to hold the members together. In order to prevent upward movement of assembly 22, 35, the assembly can be held by a washer 37 which is retained by the external body of the socket as shown in Figure 2.

As previously described, the web 24 serves to mount the keyway and the contact assembly for the central prong. The keyway comprises a ring 41 having a vertically extending post 42 which supports an upper ring 43. The upper end of post 42 is slotted as is the ring 43 to form a keyway 44 for the key 18. The contacts 46 are formed on a fiat resilient sheet of material and then bent upward whereby the lower fiat portion forms a ring 47 with the contacts extending upwardly to engage the post 17. The ring portion 41 of the keyway and the ring portion of the contact assembly are engaged by the rivet 48 which extends through the web and is riveted to the washer 49 on the other side.

The portions thus far described may be adapted to function as a tube socket. Thus, a flat plate may be suitably attached to the body portion 35 for securing the same to associated equipment. When a tube is plugged into the socket, connections are made with the various prongs. As the tube is seated, the keyway 44 and key 18 index the tube whereby the prongs 19 are positioned to engage the appropriate contact fingers.

When the tube is being operated in the higher frequency ranges, it is desirable to include additional parts to form a suitable high frequency circuit. Thus, the socket body is accommodated within a shield ring 51 which has openings 52 formed in the lower periphery thereof. The shield 51 is adapted to interfit with a resonant cavity and the openings 52 provide means for securing the same to the cavity. The shield 51 has a cylindrical portion of constant diameter and then a cup-shaped portion which extends outwardly and upwardly to accommodate the outside ring portion of the socket body 22. An upper edge 53 of the shield is adapted to be rolled over and to hold a cup-shaped upper portion 55 of the shield. Upper portion 55 houses the screen grid bypass capacitor assembly. The screen grid bypass capacitor assembly includes the cup-shaped upper portion 55 which forms an inwardly extending flange at its upper end and has a lip 56 formed in the lower edge thereof adapted to be engaged by the rolled over portion 53 of the shield.

The bypass capacitor comprises an upper capacitor formed by an upper metal spacing washer 57, dielectric washer 58, and a screen grid contact washer 59; and a lower capacitor formed by the screen grid contact 59,

dielectric washer 61 and a lower metal spacing washer 62. The capacitors are sandwiched between the flange on shield portion 55 and a flanged sleeve 63 which fits tightly within the upper plate to lock the capacitor elements together. Prior to assembly, waterproofing, dielectric, encapsulating material 64 which may be an epoxy type resin is applied at the upper and lower surface of the various washers whereby when the assembly is pressed together, the encapsulating material is forced outward where it cures and seals the assembly to maintain the same moisture tight. It should be noted that encapsulating material flows down between the member 55 and sleeve 63 to form a seal at the lower edge of member 63.

The upper and lower spacing washers 57 and 62 have an inner diameter which is greater than that of the di electric washers 58 and 61, and greater than the inner diameter of the flanges on members 55 and 63. Thus recesses 65 are formed which serve to hold the encapsulating resin and to protect against voltage breakdown between the contact washer 59 and the members 55 and 63. At their outer edges washers 57, 58, 61 and 62 extend almost into contact with the side of member 55 in order to be self-centering and yet provide space through which the encapsulating material can flow during assembly. The encapsulating material also serves as a glue which in cooperation with the close fit between member 55 and sleeve 63 serves to hold the capacitor parts assembled.

Obviously, the air gap between contact washer 59 and the inner edges of the flanges on members 55 and 63 could also be obtained without the spacing washers 57 and 62 simply by increasing the inner diamet rs of the flanges. However, this arrangement would expose the inner portion of each dielectric washer 58 and 61. The dielectric washers are extremely thin and could be easily damaged without the protective covering afforded by the flanges. Thus the use of the spacing washers results in the desired length of air gap while permitting the flanges to be extended for protection of the dielectric washers. In addition the spacing washers make possible the annular recesses 65 in which the encapsulating material 64 forms a strong protected bond.

The encapsulating material must, for long life of the 4 socket, be non-rigid, that is, it must be relatively pliable or resilient. If non-pliable, rigid encapsulating material is used it will eventually chip away because of the slight flexing movement of contact washers 59 each time a tube is inserted or removed, or when the tube and socket are subjected to strong vibrations.

The screen grid contact ring 59 has resilient contact fingers 66 which extend inwardly and downwardly. Thus the fingers 66 are positioned within the socket and are protected by the shield portion 55. When the tube is seated within the socket, the fingers 66 engage the ring 16 to make a contact with the screen grid. The contour of the fingers 66 is such that the tube is guided into the socket as it is inserted. The screen grid is capacitively connected to the shield 51 and to the equipment connected to the same.

Thus it is seen that the open construction of the socket body permits air to be blown upwardly through the socket and directed past the cooling fins 14 formed on the anode 11. A suitable high frequency circuit is formed by the screen bypass capacitors which forms an integral part of the tube.

Having thus described the invention what is claimed as new and desired to be secured by Letters Patent is:

l. A tube socket for electron tubes of the type having a plurality of prong type terminals and a ring type terminal, said socket comprising a plurality of resilient contact elements forming a plurality of contact apertures, each of said contact apertures having its axis parallel to the axes of the other contact apertures, supporting means for said contact elements comprising insulating material separating said contact elements one from the other, a metal shield ring, one end of said shield ring being mounted on said supporting means, and a circle of resilient contact fingers around the inside of said shield ring, said contact fingers being insulatingly mounted on said shield ring adjacent the other end thereof and projecting toward said one end thereof in substantial parallelism with the axes of said apertures, and the circle of said contact fingers being of large enough diameter to encircle all of said contact apertures.

2. A tube socket for electron tubes of the type having a plurality of prong type terminals and a ring type screen grid terminal, said socket comprising a plurality of re silient contact elements forming a plurality of contact apertures, each of said contact apertures having its axis parallel to the axes of the other contact apertures, supportng means for said contact elements comprising insulating material separating said contact elements one from the other, a metal shield ring mounted on said supporting means and having two flanges extending inwardly therefrom, a metal washer inserted between said flanges in spaced insulated relation to said flanges and said metal shield ring, a circle of resilient contact fingers on the inner periphery of said metal washer and forming the inlet opening for said socket, said fingers projecting from said metal washer toward the inside of the socket, and a dielectric washer sandwiched between each of said flanges and said metal washer.

3. A tube socket as claimed in claim 2 wherein a metal spacing washer is sandwiched between each of said flanges and the adjacent dielectric washer, the inner diameters of said spacing washers being greater than the inner diameters of the adjacent flanges and dielectric washers to form annular recesses, and non-rigid waterproofing insulating material in said recesses and sealing all joints between all of the washers and between the flanges and the adjacent washers.

4. A tube socket comprising a plurality of contact elements each having a resilient portion forming a contact surface, supporting means for said contact elements comprising insulating material separating said contact elements one from the other, a metal shield ring attached to said supporting means and having a metal flange extending inwardly therefrom, a metal washer positioned adjacent said flange, a ring of resilient contact means around the inside of said metal washer, a dielectric washer sandwiched between said metal washer and said flange, a metal spacing washer sandwiched between said dielectric washer and said flange, the inner diameter of said spacing washer being greater than the inner diameters of said flange and said dielectric washer to form an annular recess, and waterproofing insulating material in said recess and sealing the joints between all of said washers and between said flange and said spacing washer.

5. A tube socket as claimed in claim 4 in which said waterproofing material is non-rigid.

6. A tube socket comprising a plurality of contact elements each having a resilient portion forming a contact surface, supporting means for said contact elements comprising insula-ting material separating said contact elements one from the other, a metal shield ring mounted on said supporting means, a flange extending inwardly from one end of said shield ring, a metal washer positioned adjacent said flange and spaced toward the other end of said shield ring, means forming a resilient contact ring around the inside of said metal washer, spacing washers of metal positioned one on each side of said metal washer, said metal washer being insulated from said flange and shield ring by dielectric washers positioned one between said metal washer and each of said spacing washers, a metal supporting sleeve closely fitting inside and joined to said shield ring toward the end thereof opposite said flange, an inwardly extending flange on said sleeve, all of said washers being clamped together by said flanges, waterproofing insulating material sealing the joints between the inner edges of all of said washers and sealing the joints between the inner edges of said spacing washers and the adjacent flanges, and waterproofing material sealing the joint between said shield ring and said sleeve adjacent said flange on said sleeve.

7. A tube socket for electron tubes having a plurality of prong type terminals and a ring-type terminal comprising an annular body of dielectrc material, a plurality of contacts mounted on said body, a metal shield member encircling said body and a cup-shaped metal shield ring mounted above said body and connected to said shield member, said cup-shaped shield ring housing a capacitor assembly including a first metal spacing washer electrically connected to said shield ring, a first dielectric washer, a metal ring electrically insulated from said shield ring and having contacts thereon extending inwardly of said shield ring, said contacts being spaced along the axis of said socket from said plurality of contacts, a second dielectric Washer, a second metal spacing washer electrically connected to said shield ring and a sleeve member positioned in that order within said cup-shaped shield ring.

8. A tube socket for electron tubes in accordance with claim 7 wherein said contacts on said metal ring eX- tend radially inwardly and arcuately in the direction of said body member.

9. A tube socket in accordance with claim 7 wherein said capacitor is incapsulated in waterproofing material.

References Cited in the file of this patent UNITED STATES PATENTS 

